SAMPLE-SELECTION
Vehicles were selected in an attempt to best represent the broad
range of vehicle types available. Individual vehicles were
selected on a convenience basis. All vehicles were products
of domestic manufactures. Two cars were selected, a 1993
model and a 1997 model. Also a 1997 minivan, a 1996 pickup
truck and a 1996 mass transit bus were selected for
measurement.
SAMPLE-SIZE
5 vehicles were chosen for measurement.
MEASURED-PARAMETER
3-axis magnetic field wave capture at sampling frequencies of
160 and 10,240 Hz.
METHODOLOGY
3-axis magnetic field probes were attached at three body
positions (head, waist and ankle) on multiple vehicle
occupants (or mannequin equivalents) during interior
measurements of the vehicle.
The same 3-axis probes were attached to a staff at heights
of 10, 60 and 110 cm during exterior measurements, and
located at specified locations around the vehicle.
The signal from each axis of each probe was measured and
recorded using both a low and high-frequency
analog-to-digital convertor. Each wave-capture measurement
lasted 0.2 seconds, resulting in a base frequency of 5 Hz.
The low frequency convertor sampled the waveform at a
frequency of 160 Hz during the 0.2 seconds (a total of 32
measurements). The high frequency convertor sampled the
waveform at a frequency of 10,240 Hz during the 0.2 seconds
(a total of 2048 measurements). The low frequency convertor
was used primarily to characterize the static portion of the
field. The high frequency convertor was used to
characterize the spectral components of the magnetic field.
The waveforms for all probes were typically captured at
intervals of approximately 10 seconds.
INSTRUMENT-NAME
SAMPLING-INTERVAL
The waveforms for all probes were typically captured at
intervals of approximately 10 seconds.
SAMPLING-DURATION
Each session lasted on the order of one half-hour, during
which waveforms were captured continuously, or nearly
continuously at the 10 second sampling interval.